yellow fever

Yellow fever is an acute viral infection caused by the yellow fever virus and transmitted by infected mosquitoes. It typically presents as a febrile illness with constitutional symptoms and, in its severe form, can progress to viral hemorrhagic fever with shock and multi-organ system failure. Precise prevalence estimates are not well established, and the condition is primarily seen in endemic regions where exposure to the virus is common. As an infectious disease, it does not have a genetic basis or inherited pattern.

Individuals with yellow fever often initially experience high fever, nausea, headache, and chills, with many also showing laboratory evidence such as increased circulating IgM levels and viremia. As the disease progresses, symptoms may include vomiting, abdominal pain, and myalgia, while some patients develop signs of liver injury, as indicated by elevated alanine aminotransferase levels. Bleeding manifestations, such as hematemesis, abnormal bleeding, or excessive bleeding after a venipuncture, can occur in a subset of patients, along with less common features like acute kidney injury, metabolic acidosis, and decreased serum bicarbonate levels. Not all individuals experience all features, and severity varies considerably.

Yellow fever is caused by infection with the yellow fever virus, a member of the flavivirus family. Transmission occurs primarily through the bite of infected mosquitoes found in tropical and subtropical regions. The condition is not linked to any genetic mutations or hereditary factors; rather, it is acquired through environmental exposure. Since there is no known inherited component, family members are not at increased genetic risk from one another.

Currently, management of yellow fever focuses on supportive care and symptom management, as there are no specific foundational or approved treatments available. Care is tailored to the individual and typically involves a multidisciplinary team that provides ongoing surveillance and monitoring to detect complications early. In severe cases where hemorrhagic symptoms, shock, or multi-organ failure occur, prompt medical intervention and intensive supportive care are essential. Patients should discuss treatment options with their healthcare team to determine the most appropriate approach for their specific situation.

The clinical course of yellow fever is highly variable. While many individuals recover from the milder form of the illness, those who progress to the severe hemorrhagic phase may experience significant complications, including shock and multi-organ failure. With current standards of care, outcomes have improved over the years, although the course of the illness can differ widely depending on the severity of symptoms and timely access to supportive care. Outcomes described in medical literature continue to evolve as standards of care improve, and families are encouraged to connect with infectious disease specialists to discuss long-term care planning.

Yellow fever remains an active area of research, with several clinical trials currently investigating new treatment approaches and supportive care strategies. Individuals interested in clinical trials can search ClinicalTrials.gov or consult their care team about eligibility.